With electronic signal switching speeds currently in the gigahertz range and still increasing, deleterious transmission line effects have become more prevalent. For example, the electrical connection of two printed circuit boards (PCBs) in an electronic system, normally accomplished by way of wire cables and connectors, or by way of standard board-edge connectors, often results in relatively long transmission lines between the two boards, allowing unwanted signal reflections to exist. To mitigate these effects, shorter transmission lines between electronic components in an electronic system are advantageous.
To that end, direct connection between two PCBs in the absence of a standard connector is desirable, as the transmission line lengths for such a connection scheme are reduced to a minimum. The most direct connection between two PCBs involves soldering the edge of one PCB to the side of the second PCB. Unfortunately, such a configuration is typically mechanically unstable, making the process of soldering the first PCB to the second difficult.
Thus, the use of some kind of PCB interconnection structure or method that minimizes signal line lengths between two PCBs while allowing the relative position of the two PCBs to remain stable during the soldering process would be advantageous.
Specific embodiments according to the present invention, to be described herein, provide an effective structure for electrically coupling an edge of a first PCB to a side of a second PCB. The first PCB has a plurality of plated split holes incorporated on the edge of the first PCB that is to be attached to the second PCB. An electrically conductive leg is held within each of the plated split holes. In effect, the legs serve as solderable leads for the first PCB. The legs help keep the first PCB steady while the leads are soldered to the second PCB. The legs also provide the short electrical connections required of high-speed electronic signals being transmitted between the first and second PCBs.
Embodiments of the present invention also involve a method of producing a structure for electrically coupling an edge of a first PCB to a side of a second PCB. During the design of the first PCB, a plurality of plated split holes are incorporated along the edge of the first PCB that is to be coupled with the second PCB, with the plated split holes being spaced at a substantially consistent distance along the edge. Next, a coil of electrically conductive wire is placed along the edge of the first PCB, with each successive turn of the coil of wire being placed within each successive plated split hole. The distance between each turn of the coil is approximately the same as the distance between adjacent plated split holes. The coil of wire is then cut on both sides along the edge of the first PCB, leaving an electrically conductive leg soldered to each plated hole. Additionally, connection structures made according to the disclosed method embodiments are also embodiments of the present invention.
Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.